(1) Field of the Invention
The present invention relates to a device for supplying fuel to an energy producing installation onboard a liquefied gas transport ship from a liquefied gas tank of said ship.
(2) Description of Related Art Including
In a liquefied gas transport ship, for example of the methane tanker type, an energy producing installation is provided to meet the energy needs of the ship's operation, in particular for the propulsion of the ship and/or the production of electricity for the vessel's equipment. An installation of this type commonly comprises heat engines consuming gas coming from an evaporator which is fed from the liquefied gas cargo transported in the tanks of the ship.
FR-A-2837783 provides for feeding an evaporator of this type and/or other systems needed for propulsion using a pump submerged at the bottom of a tank of the ship. A pump thus placed has drawbacks when one wishes to feed the propulsion of a methane tanker with gas during ballasted travel, i.e. when the tanks have been discharged. In this case, it is necessary to leave a liquefied gas nose at the bottom of the tanks sufficient to enable operation of the pump. Indeed, if the liquid level is too low, the pump is led to pump, at times, a mixture of liquid and gas due to the movements of the cargo, which risks stalling or even seriously damaging the pump (poor cooling, intensity drop, etc.).
FR-A-2832783 proposes to avoid these problems by surrounding the pump, still placed at the bottom of the tank, with a collecting housing provided with check valves, with a view to ensuring continuous immersion of the suction of the pump even when the tank is not very full and the ship is subject to pitch and roll motions. The reliability and effectiveness of this device are limited, in particular because the valves can become stuck and no longer perform their function, and because the filling of the collecting housing requires sufficiently regular wave motions, which fill the housing by submersion.
FR-A-2876981 describes a supply device in which one provides a pump on the bridge of the ship, connected to a liquid ejector arranged in the bottom of the tank. This solution requires complementary elements on the bridge of the ship, in particular an auxiliary reservoir, the thermal insulation of which must be ensured.